Did strange clouds foretell China quake?

Phil Plait writes Slate’s Bad Astronomy blog and is an astronomer, public speaker, science evangelizer, and author of Death From the Skies!

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Did this phenomenon foretell the coming of the earthquake?

No, of course not. I knew right away what these were: high altitude icy clouds. Sunlight passing through them gets diffracted, broken up into colors like a rainbow. Under normal circumstances you get a complete halo around the Sun, which can be heart-stoppingly beautiful. Different kinds of clouds produce different effects (fire clouds are particularly cool).

In the case of the colors seen in China before the earthquake, the clouds were patchy, which is why you don't see a continuous stream of color horizontally. Instead, spots of local color are seen. The order of the colors is clearly ROYGBIV, the same as in a rainbow or circumhorizon arc. Not only that, but the videos were taken in mid-afternoon, around 2:00 p.m. local time, and the Sun would have been high in the sky, just where it should be to get this effect.

I see things like this all the time, because I do something a lot of folks don't do: I look up. Seriously, it's that simple. When you do that, you get to see halos, sundogs, and arcs quite often. It's usually in the winter, but it doesn't have to be. You just need high, icy clouds.

So what we have here in China is just a normal, if not exactly everyday, atmospheric effect. If people just looked up more, they would have seen this for what it is, a pretty sight in the sky that has nothing at all to do with the earthquake that would change their lives so drastically less than an hour later.

Remember: post hoc ergo propter hoc -- after this, therefore because of this -- is called a logical fallacy for a reason.